What turns your genes on, and off?

Drs. Oz and Roizen Health Advice

QI thought I was born with my genes (some from Mom, some from Dad), and they made me who I am. Now I hear that how you live day-to-day turns genes on and off. Does that change who I am, basically? — Mitch D., Mystic, Ct.

AYou were born with a set of genes. The DNA-containing chromosomes in those genes determine your gender, your eye color, even your sensitivity to sound. But not all genes are active all the time. And about 80 percent of your genetic material is made up not of genes but of gene switches (which we are just beginning to understand). These switches cause changes in the way a gene works; this is called gene expression — a smile or a grimace, if you want to think of it that way. Switches can be prodded by things like toxins, stress, behavior and diet into expressing themselves as they were intended to — or not — without altering your DNA. So you stay the same person, but one who, unfortunately, develops cancer, muscular dystrophy or mental illness, for example.

So, how can you help your genes do their job of keeping you healthy, happy and strong?

•Limit exposure to toxins. Have your house tested for radon (radon occurs naturally in the ground and is the second-leading cause of lung cancer in North America). Eliminate plastics containing bisphenol-A (BPA) and phthalates from your home. Use paints with a low- or no-VOC (volatile organic compounds) rating. Wash fruits and vegetables in water to remove pesticide residue and bacteria. And stay away from smoke (cigarettes, charcoal grills and fireplaces).

•Chill it. Chronic stress can flip the switch on genes, making you more susceptible to cancer, heart disease and depression. Meditation for 10 minutes a day lowers levels of the stress hormone cortisol.

•Eat smart. Eliminate the five food felons (trans fats and most saturated fats, added sugar and sugar syrups, and any grain that isn’t 100 percent whole), and if you are overweight, drop 10 percent of your body weight. It’s a sure gene pleaser, and you’ll make your other jeans happy too.

QIt’s official; I’m menopausal. Now my gynecologist suggests I start hormone therapy, even though I don’t have many hot flashes and my brain fog seems to have lifted. Does this make any sense? — Susan G., Chicago

AHormone therapy — progesterone/progestin and estrogen for women with a uterus, or estrogen alone for those without one — is safer than once thought. Evidence shows that HT is OK for easing menopause-related symptoms such as hot flashes, cloudy thinking and heart palpitations, and it provides protection against heart failure and heart attack without increasing the risk of a blood clot or cancer, especially when combined with two baby aspirins a day and a half-glass of warm water before and after.

The best benefits come if you start HT soon after your periods stop — and stay on it for up to 10 years. (This info comes on the heels of two studies: One found that women using an estrogen patch or gel, on the skin or in the vagina, cut their risk of heart attack by 38 percent to 44 percent; the other found that the patch increases insulin sensitivity — good protection against diabetes.)

HT isn’t for every woman: If family history, obesity or a chronic disease increases your risk for cardio problems, dementia or cancer, it’s important to use lifestyle changes to control menopause symptoms, protect your heart and reduce your cancer risk. In fact, everyone should adopt these, whether they start HT or not: